IRAK1 and inflammatory bowel disease: Further analyses of the genes involved in the downregulated pathways showed that genes linked to prostaglandin and leukotriene synthesis (ALOX5, ALOX15, ALOX5AP, PTGS2), pattern recognition (NOD2, TIFA), TH17 differentiation (IRAK1) and colon carcinogenesis (MAPKAPK2, MAP2K3) were upregulated in active IBD (Figure 2C).